Silicone calk for glue and stitch

I am looking at building a cheap one sheet plywood boat to haul extra gear when kayak camping with the wife. I want to build it a bit more sturdy than most of the people do though. I was looking at glue and stitch and was wondering if instead of a marine based epoxy (like M3 4200) if regular silicone could be used in place of it? Simply for a bit of cost savings (3M is about 3x as expensive)

 

Silicone is not really a structural element, only a sealant, and you will often notice that the tube says "not suitable for inderwater use".

 

You should use sikaflex...excellent adhesive:

http://www.ukstainless.co.uk/product.asp?idproduct=99

Like most things in life - you only get what you pay for. This is an excellent adhesive for marine use. We use it all the time.

 

Thanks for the info. Thats not a bad price.

 

Welcome to the forum.

You can't substitute an adhesive/sealant for epoxy. 3M-5200 (what I'll assume you meant with M3 4200) is about the most aggressive adhesive/sealant available, but still isn't a suitable substitute for epoxy. Modulus of elasticity is the real issue and though good, not even remotely close to what epoxy provides. You'll find you can't "wet out" fabrics with these polyurethane adhesive/sealants, so their value in taped seam construction (stitch and glue is a method) is dubious at best and highly not recommended.

Do yourself a big favor and log onto westsystem.com and systemthree.com and download their free "user's guides" and the "epoxy book". These will nurse you through the basics.

Lastly, most of these adhesive/sealants cost more than epoxy, ounce to ounce, so not any savings either. The convenience of a single part goo is appetizing, but you do need to understand the physical attributes of the materials involved.

 

Do you have any recommendations for inexpensive epoxy? Im trying to do this on the cheap. Itll basically just get beat around a couple times a year.

Something like the West System Six10?

 

West System and System Three are the two most expensive brands. Six10 and T-88 are premixed, thickened epoxy and you pay through the nose for this convenience.

Marinepoxy
http://www.duckworksbbs.com/supplies/epoxy/marinepoxy/index.htm

RAKA
http://www.duckworksbbs.com/supplies/epoxy/raka/index.htm

B&B
http://bandbyachtdesigns.com/533-2/

What design are you building?

 

Welcome, Woody213. Why not find an old kayak on the cheap and remove the paddlers seat and cover it with a closable cargo hatch and tow that to the camp?

 

US Composites is pretty inexpensive.

 

US Composites makes some good products, but typically are 20% or more higher than the other discount formulators.

 

still way less than the premium marine epoxy suppliers

 

Agreed . . .

 

$70.00 for 1/12 gallon kit from US Composites is a lot cheaper that the others listed.

 

The "others listed" range from $55 to $65, of course depending on quantity. Price breaks typically start at 3 gallons or more.

 

All I saw on the others $90 to 96 for the 1 1/2 gallon kit which includes hardener for small stitch and glue.$128 for 3 gallons or $298 for 5 gallons.

http://www.shopmaninc.com/