Patching plastic canoes

[Daniel in Ak]

Checking out another thread brings to mind what would be a great way to patch a plastic canoe?
I had mine done with plastic weld,but we dropped it pretty good on a gravel bar and it busted again.Daniel

 

[Alaskacanoe]

patching polyethelyene

patching polyethelyene

Patching Polyethelyene canoes ( Coleman, or Pelican) brands is difficult due to the material shrinks and expands quite alot at different temperatures. It moves more than you would think, and no mater the material you attempt to weld or adhere to it, it will shrink up or expand differently so soon it just falls off. Or in the case of the post above, It fell of due to being dropped...
Even the Weld kits can't do the perfect fix for the same reasons.
I have found that I have to basically sew a patch in these canoes.
I drill several 1/8 inch holes about a half inch apart around the area I need to patch and then use a two part bumper repair material that you can get at the Auto parts store. I push the paste material thru the drilled holes, and put some paste on both the inside and the outside of the canoe. I make sure I have the ample mixed paste on both sides. You can smooth it pretty good with a putty knife or a popcicle stick.
This way the material is sewn together, and will hold much better. The original material will never really accept the new material, but it won't peel off and is tight enough to keep it from leaking. I noticed that the bumper repair material wears a little faster than the original Plastic or Polyethelyene, so building it up is a good idea when you patch.
I have tried several products from Marine-tec, epoxy, etc. and find that the bumper repair material works the best that I have found so far.
If any of you have success with some other way.?. I would love to hear about it..

 

[sayak]

Hey Alaskacanoe-

Hey Alaskacanoe-

What brand bumper repair glue do you use, and where do you buy it in Soldotna?

 

[Alaskacanoe]

bumper repair

bumper repair

This stuff is made by Bondo, and works as good as any. Its cheap about $5.00 for the two part . I have used other brands as well. I purchased a larger repair kit from the Riverside Auto parts in Soldotna.
I came upon this by accident.
A few years ago I was at a Auto body repair shop in Soldotna, and watched a fellow repair a snowmobile cowling using the technique of drilling the holes and then sewing it together with the two part flexible expoxy material.
He said that vibration usually tears most repairs apart, and this sewing ideas was working best for ATV's, Snowmobiles, Boat motor cowlings, etc.
Max

 

[sayak]

Bondo repair

Bondo repair

Cool! Thanks!

 

[Daniel in Ak]

cool.....thanks a mil for the advise and picture,sure helps out.Daniel

 

[fullkurl]

Heres the best method...

Heres the best method...

AKCanoe's method looks great. I've used that very product for bumpers and flexible parts many times but I would be a bit concerned about the extreme flexility issues and cold water you'll be encountering.
I've repaired plastic canoes, heres how I did it:
(I'd skip the sew process altogether.)
I use SIKAFLEX urethane. This is the urethane that is used for windshield installations. It dries rubbery and firm yet is totally flexible. Kinda like a rubber ball. It sticks to everything.
Prep around the canoe's hole area with 36 or 24 grit sandpaper. Make sure you remove all dust and grease or any other contaminant from the area.
Use a chaulk gun to apply the SIKAFLEX around the edge of the repair. Sikaflex is a Swedish made urethane available at quality glass shops, usually around $10 a tube. One tube should do it. Lay your patch over the hole--You should be using a "like" plastic material for the patch, preferably the same material as the canoe itself. Make sure you sand the patch to be applied as you did the canoe itself (24 or 36 grit.) Lay the Sika on the area and then the patch. I'd use some saran wrap and lay it over both sides of the repair and then clamp it with visegrips if you can get to it, or maybe some dumbells or something if the canoe is laid on its side. It will really solidify the repair. Any excess urethane can be trimmed away with a razor blade.
The stuff dries overnight and will outlast the canoe!

I've repaired countless things like this with this product, including plastic canoes and snogo cowls, I've never had a failure ever. The key is in the incredible adhesive properties and total flexiblity.
Watch getting this stuff on your hands, its black, sticky and nasty to remove. Their fast cure product works best warm.
Frank

 

[Daniel in Ak]

hey Fullkurl,
That sounds way easy for a slow one like myself and I really appreciate the advise and help,If I ever get around to it I'll get some pictures up and show everyone.Again thanks.Daniel

 

[Alaskacanoe]

repair kit

repair kit

Monday I will be at the window place getting some of this stuff. I hope it works as well for me as it has for you.
It has truly been frustating to fix these great all purpose canoes. Like I have said before that every product etheylene based or otherwise has not held onto the original canoe material. I even called Pelican ( makers of Coleman canoes) in Canada where they build them and was told that They do not have a repair suggestion or a kit, or welder etc. that they can not..recommend due to legal responsiblities, So I asked to talk to someone in the actual manufactureing of these craft. the manufacturing engineers for Pelican told me the reason... the reason that materials won't stay fastened to the material very well. He said, is that Polyethylene materials are oil based and because of that oil base, they are actually a liquid in a semi solid state. No possible way as of yet to keep them so solid that time, temperature and enviroment will not change the actual molecular structure. When heated or cooled just a few degrees, the material expands and contracts and stretches the material enough that it can be measured. He said that is why the metal trim holes on the canoes are liberal to a point. When I asked why the Weld kit material ( advertised as the same material as the coleman canoe original RamX) will not hold for extended use, he told me about the molding process and that you would have to be exact in temperature in the surrounding material you are welding it to-- to make it hold. (Something he said was near impossible). And it would have to be from the same exact batch and the same age, as Ozone and other enviroments play a part. They have a recipe that they follow as exact as possible, but he said that they are continually trying to improve, by adding Ozone protective chemicals, or even using different additives as permitted in the Patent limits.
I am excited though to try something new to me, as repairing canoes is something I do on a daily basis in the summer time. I have a fleet of over 36 canoes and 12 kayaks of various materials and so I spend alot of time keeping them afloat.
Thanks again for the product suggestions and the method, I am really hoping that this is the cure.. It sounds like it has worked really well for you.
Question, Can you sand this material and paint over it?
Max

 

[fullkurl]

Urethane...

Urethane...

Max, given the rubbery nature of the "set" urethane its not condusive to sanding and painting. A guy could probably scuff pad the repaired urethane area and shoot it with a dusting of paint.
The key to a good repair is to get a good etch into the plastic with the sandpaper or grinding disk. You will see how incredibly sticky and adhesive the product is soon after you chaulk-gun it on. Clamping or weighing down the repair will really help too.
Ask for SIKAFLEX. Novus and other glass shops use it in Fairbanks. I've been repairing things with this stuff for twenty years. Most guys throw away things that I've been able to bond and repair.
It works excellent for hinge material that is broken off of sled cowls...

 

[Alaskacanoe]

This is why

This is why

This is why this directory is such a great place.
you can get information about anything.
I like the fact that it is a clean and proactive inviroment.
I just want to say..... well ....... I love you man...
xxo

 

[springer]

Which version of sikaflex do you use? There seems to be 5. They are 291, 291-lot, 292, 295 and 296.

Max, given the rubbery nature of the "set" urethane its not condusive to sanding and painting. A guy could probably scuff pad the repaired urethane area and shoot it with a dusting of paint.
The key to a good repair is to get a good etch into the plastic with the sandpaper or grinding disk. You will see how incredibly sticky and adhesive the product is soon after you chaulk-gun it on. Clamping or weighing down the repair will really help too.
Ask for SIKAFLEX. Novus and other glass shops use it in Fairbanks. I've been repairing things with this stuff for twenty years. Most guys throw away things that I've been able to bond and repair.
It works excellent for hinge material that is broken off of sled cowls...

 

[big_dog60]

I have seen the product used before (on buildings) I dont think you can paint it with any normal paint. The paint will crack and fall off quite quickly.

 

[yukonPike]

At work we use a compound called Rapid Rubber (Three M?). to put patches on steel and in some instances rubber lines. The compound is a two part system used with a special mixing gun. We put the compound on and then place a rubber patch on top of it. It is flexable and can withstand thousands of gallons a minute slurry (water and sand) flow on the patch. It is not cheap fifty or so per tube and the you need caulking gun to apply it.

 

[fullkurl]

sika

sika

Which version of sikaflex do you use? There seems to be 5. They are 291, 291-lot, 292, 295 and 296.

Interesting product, Pike. Sounds good.

For the less expensive:
I've used the Sika 291, but any of them should should do the job also. I would say the longer dry time might be a good idea with plastic (291). They make a 255fc which is a very fast cure. I glued a model airplane wing on with it and it held great. I since gave that up--too many crashes.

Just make sure the canoe area is scuffed (gouged) well--use a 24-36 grit on a grinder or polisher. Most plastics continue to ooze a mold release (on a molecular level) when sanded, but the sika-flex doesn't seem to mind, just wipe the repair area with a thinner and allow to dry before applying the product.

Frank

 

[Mr. Pid]

I've used Sika products for a long time. It is good stuff but I'd consider it a temporary repair on a canoe.

Here are some hints. If you get it on you, alcohol will get it off. The tubes have a shelf life. If you buy a fresh tube today and don't open it, it'll be cured in the tube by next summer. Once you open a tube, it'll cure even faster. Heat makes it easier to gun and tool. Nothing extreme, just put it in front of your truck heater for 10 minutes or so and it'll flow better.

If my Coleman canoe needed long-term repair I'd go to NAPA and buy a flexible body parts repair kit. If I needed something as a temporary fix to get me home I'd use Gorilla tape. That stuff is awesome.

 

[bushrat]

Ah, I have (not so) fond memories of trying to "weld" a good-sized hole on keel of coleman one evening during moose season, didn't have tape or anything else. Took the front piece that holds styrofoam out and used the tip of axe heated in fire to try to weld the similar plastic together. Pretty touch and go affair as you can easily end up making the hole bigger. I need to get me some of that sikaflex from the sounds of it, have gone through five colemans over the years; man they are the absolute best for lining and sliding over rocks. Fiberglass ain't bad either and is a lot easier to repair. One thing I've considered, since colemans invariably wear holes in that hollow keel, would be to pour something in there to fill that permanently, but not sure if it would take the bending and twisting and hold. If they made that keel solid/filled a guy would sure get more life out of the canoe.

 

[RainGull]

I thought you were gonna say that you used pitch and birch bark.

 

[tonbuc]

Hi,

I came across this site and thread yesterday while searching for methods to repair Polyethylene Kayaks and found the information very valuable. I was especially interested in reading about Frank's Sikaflex 291 solution, but also wanted to add a few bits and pieces of my own which others may find to be of some assistance. The Sikaflex solution sounds like the most cost effective method of repair. I phoned Sikaflex Tech support (Aust) about a month ago but at the time was told they manufacture no product suitable for use on HDPE (High Density Polyethylene), but I'm also guessing that no one in their technical department has ever tried to use it to repair Kayaks, and it sounds like Frank has had quite a lot of successful experience in this area.

Please note, I have not tried any of the items or procedures below personally. At this stage I am still trying to gather every possible piece of information I can find before attempting to perform my own repair on a Polyethylene Kayak which has developed a slight hole on the base near the keel section.

Aside from the obvious plastic welding, here are a few other suggestions.

In terms of adhesives suitable for HDPE (High Density Polyethylene) - Loctite 401 in conjunction with the Loctite 770 Primer is probably the most promising adhesive for bonding HDPE patches, not certain however of its water resistant/proof properties - Loctite suggested using the adhesive for the patch followed with a suitable RTV silicone around the edge to form a waterproof barrier.
See http://tds.loctite.com/tds5/docs/NEW-CA401-EN.PDF and http://tds.loctite.com/tds5/docs/770-EN.PDF for technical datasheet. The product specs for 701 appear to suggest that 701 is quite resilient to water even after 5000 hours of exposure.

3M also make a product called Scotch Weld DP-8005 http://www.3m.com/intl/kr/img/adh/adhesives/dpseries/DP8005.pdf which will bond HDPE, however it breaks down when exposed to water for prolonged periods, further, you need to purchase a special dispenser which is very expensive (many times more than the actual adhesive).

Several days ago I came across a product that also sounds quite promising called "Patch 'n Go" http://www.moldingraphics.com/Foreign/1Italian/PNG.htm , essentially it's a form of semi solidified plastic compound which can be moulded and shaped to suite the crack/hole area and is then activated by use of a low burning flame causing it to weld to the surrounding plastic. Unfortunately I cannot locate a supplier/distributor here in Australia, however in your part of the world it appears to be readily available.

Apparently flame treating the surface of Polyethylene using the correct setting on a propane torch can also provide the benefit of changing the PE surface molecular structure enough to allow it to bond with other types of adhesives that may not traditionally bond to PE.
see: http://www.combust.com.au/plastic/polyol.htm & http://www.a-a-i.net/polyethylene.htm for detailed procedure and description. I am wondering whether the flame treating could be used in conjunction with the sanding suggested by Frank to further increase the bonding of the Sikaflex 291 to the plastic?

Some other useful links:
http://www.plentypupule.com/weldkit.htm
http://oakorchardcanoe.com/detail.php?product=2440
http://www.patchngo.com/ (note: this is not the same as the "Patch 'n Go" mentioned above.
http://www.marinetex.com/PRODUCT%20PAGE_files/All%20PolyDura%20Info/Poly%20Dura%20Directions.htm
http://www.polyprocessing.com/pdf/technical/RepairRotomoldedPolyethyleneParts.pdf

Hope someone finds the above useful.

Tony.

 

[fullkurl]

Great info, Tonbuc. Thanks for the links and
welcome to the O.D.D. site.
Mr. Pid is correct, I'd definitely be hestitant to load up any urethane repaired canoe for a thousand mile solo float of the Yukon!
But for the low buck among us, it can be a cost-effective repair.
I actually used Sikaflex to sheetmetal patch repair an engine block that had thrown a rod. (Honda Civic circa 1978).

Mark, no bush dweller should be without some quality urethane like Sika for bonding/sealing. If I can pick some up in the near future, I'll send some your way. PM me your PO box address.

Frank

Hi,

I came across this site and thread yesterday while searching for methods to repair Polyethylene Kayaks and found the information very valuable. I was especially interested in reading about Frank's Sikaflex 291 solution, but also wanted to add a few bits and pieces of my own which others may find to be of some assistance. The Sikaflex solution sounds like the most cost effective method of repair. I phoned Sikaflex Tech support (Aust) about a month ago but at the time was told they manufacture no product suitable for use on HDPE (High Density Polyethylene), but I'm also guessing that no one in their technical department has ever tried to use it to repair Kayaks, and it sounds like Frank has had quite a lot of successful experience in this area.

Please note, I have not tried any of the items or procedures below personally. At this stage I am still trying to gather every possible piece of information I can find before attempting to perform my own repair on a Polyethylene Kayak which has developed a slight hole on the base near the keel section.

Aside from the obvious plastic welding, here are a few other suggestions.

In terms of adhesives suitable for HDPE (High Density Polyethylene) - Loctite 401 in conjunction with the Loctite 770 Primer is probably the most promising adhesive for bonding HDPE patches, not certain however of its water resistant/proof properties - Loctite suggested using the adhesive for the patch followed with a suitable RTV silicone around the edge to form a waterproof barrier.
See http://tds.loctite.com/tds5/docs/NEW-CA401-EN.PDF and http://tds.loctite.com/tds5/docs/770-EN.PDF for technical datasheet. The product specs for 701 appear to suggest that 701 is quite resilient to water even after 5000 hours of exposure.

3M also make a product called Scotch Weld DP-8005 http://www.3m.com/intl/kr/img/adh/adhesives/dpseries/DP8005.pdf which will bond HDPE, however it breaks down when exposed to water for prolonged periods, further, you need to purchase a special dispenser which is very expensive (many times more than the actual adhesive).

Several days ago I came across a product that also sounds quite promising called "Patch 'n Go" http://www.moldingraphics.com/Foreign/1Italian/PNG.htm , essentially it's a form of semi solidified plastic compound which can be moulded and shaped to suite the crack/hole area and is then activated by use of a low burning flame causing it to weld to the surrounding plastic. Unfortunately I cannot locate a supplier/distributor here in Australia, however in your part of the world it appears to be readily available.

Apparently flame treating the surface of Polyethylene using the correct setting on a propane torch can also provide the benefit of changing the PE surface molecular structure enough to allow it to bond with other types of adhesives that may not traditionally bond to PE.
see: http://www.combust.com.au/plastic/polyol.htm & http://www.a-a-i.net/polyethylene.htm for detailed procedure and description. I am wondering whether the flame treating could be used in conjunction with the sanding suggested by Frank to further increase the bonding of the Sikaflex 291 to the plastic?

Some other useful links:
http://www.plentypupule.com/weldkit.htm
http://oakorchardcanoe.com/detail.php?product=2440
http://www.patchngo.com/ (note: this is not the same as the "Patch 'n Go" mentioned above.
http://www.marinetex.com/PRODUCT%20PAGE_files/All%20PolyDura%20Info/Poly%20Dura%20Directions.htm
http://www.polyprocessing.com/pdf/technical/RepairRotomoldedPolyethyleneParts.pdf

Hope someone finds the above useful.

Tony.