C-Forum

To use melted ABS I suppose you need to be smarter then the ABS. I am, as we speak, doing a test melt. I don't know how much MEK to put with the little pieces of ABS. How small do you cut up the ABS? How long should it take to melt? How long after melting should I apply it?

I guess just paint it on? Any special brush? I should prolly paint after to avoid sun damage?

Anything else I need to know?

thanks, Chris Kelly

Chris,

I just cut it into 1-2 inch squares. I put in enough acetone to not actually cover the chunks and let it sit for two days, stir and see if you need to add more.

I applied with a putty knife - easy to clean and resuse. I just scrape any residue off with a razor right after the application. A brush will be trashed after each layer you apply.

Chris,

I bought a 10' section of 2" ABS pipe then cut it in half lengthwise. I then it into pieces just long enough to fit into a new paint can. I then filled the can about half way with MEK or acetone and stirred it every day.

The ABS mixture dries by evaporation so the surface dries first. I would therefore recommend several thinner coats. I tried filling in a hole in the stern of my canoe by dumping a bunch of ABS into it. The ABS on the surface dried first, trapping a lot of wet ABS inside. It never did dry until I cut several holes into the patch to let air in.

A thin coat has more MEK/acetone in it so I would think that it would do a better job of melting the boat's ABS and therefore make a better bond. I haven't tried using a thick paste yet so I'm only assuming. Use the cheapest brush that you can find.

Jim

I've been using small mason jars, cutting or breaking the ABS into small pieces, maybe 1/2" x 1" or smaller then covering them with acetone. Every time I walk by for a day, I'll shake the jar. By day two, it's started to become a paste and I'll stir it a couple of times, then it it ready - adding acetone if it is too thick, adding ABS if it is too thin (which adds some time for the new material to dissolve).

I have been using tongue depressors to apply the paste and remembering the guidance to use thin layers. I have been letting the layers dry for anywhere between 12 and 24 hours before adding another layer - a layer being about 1/16" to almost 1/8" thick.

I've done this on three canoes with great success - we've river tested them over the last couple of months and they've held up fine. However, on the last boat I patched, I've had an "uh oh" - I'll post pics shortly and my own query for the ABS putty experts...

I realize my post about putting a 2 layer S-glass patch on ABS was boring, but I recommend it as an alternative to glue sniffing and painting, at least for some purposes.

Can you also apply the ABS paste on the outer vinyl layer of the boat? Or does it just adhere to the ABS layer underneath the vinyl? It must bond to both if you're feathering the patch out over the broader area around the damage, right?

ezwater wrote: I realize my post about putting a 2 layer S-glass patch on ABS was boring, but I recommend it as an alternative to glue sniffing and painting, at least for some purposes.

Well, given my experience and abilities with resin and glass - this ABS approach is simpler and has been largely successful. With resin, I end up with a mix of stuff that is "cooking" sometimes faster than I can work and for some reason, I never seem to get the fabric down smoothly - I end up with clumps, stuff sticking to my gloves, etc. Then, after a couple of weeks of wear, I end up with the fiberglass fuzzies. I spend upwards of $60 for the small can of resin, hardener, and some pumps, and don't use it fast enough and end up with it going bad (last time I mixed up a batch it wasn't hard after three days). And as for sniffing glue, the fumes coming off of the resin can't be much better than any from the ABS/acetone mix... All in all, my glass work experience is not very satisfactory - I'm a certified glass klutz. I'd pay someone else to do it, but there doesn't seem to be anybody in my area that does it!

What does appeal to me about patching with ABS is that I am patching the boat with the same material - that should have the same properties - flexibility, thermal expansion/contraction, etc. Also, I can prepare small batches of it with minimal investment. And, until this most recent experience, it's worked well.

milkman wrote:Can you also apply the ABS paste on the outer vinyl layer of the boat? Or does it just adhere to the ABS layer underneath the vinyl? It must bond to both if you're feathering the patch out over the broader area around the damage, right?

In patching both smaller gouges and larger worn areas, I have spread the mix over both exposed ABS and vinyl and it has bonded well.

In covering areas adjacent to kevlar grunch pads or exposed due to breakage of the grunch pads, it was not surprising to see that the past does *not* bond well to the grunch pad material.

sbroam, have you considered whether your delayed itchies are due to epoxy sensitivity rather than to glass fibers?

I started working with epoxy back in the early 60s, and at that time, most of what was on the market was nasty! I got sensitized, badly enough that I had to switch temporarily to vinylester for repairs.

West epoxy is much less sensitizing, but some people do develop sensitivity to it.

Glass fiber itchies are likely to develop only if you do a lot of sanding or cutting and fail to avoid the microfibers. I have never had a serious problem with glass fibers, even when I have had to do a lot of sanding or cloth cutting.

When I work with West epoxy, I take only two basic precautions. I work in a well ventilated area, and I wear latex or, preferably, vinyl gloves. I am very careful not to spread resin onto my arms, and if I cut or foul a glove, I pull it off and get another.

I am fascinated by the ABS treacle method, but apart from mostly positive anecdotes, I lack lab results showing what this paint-on material achieves. As for FRP, we had good lab results even back in Walbridge's Boat Builder's Manual.