ABS repair question re. exposed foam core

[boatbuster]

My buddy has a Royalex boat with a smashed end. In addition to multiple cracks there is a section where the outer layer is gone. He does not want to give up on this boat even though it is old and brittle. We are going to try to cover the damage with ABS plastic but I think we should fill in this area where the foam core is exposed. But with what? I thought about scraping off the foam and using GFlex or marine epoxy. What have others done in this situation?

Thanks in advance for your replies.

[zappaddles]

Lots of G-Flex and carbon-fiber/kevlar hybrid cloth. Vee out the foam enough to give some G-5 (West systems 5 minute epoxy) time to hold the hull in position until the G-Flex/hybrid cloth patch sets up. Use 2 patches with the 2nd being 3-4 inches wider on each edge than the first.

Never done this particular repair but seems like it'll work as good as anything else.

[boatbuster]

Here's a photo of the damaged area

Here's a photo of the damaged area

Thanks...I have used that method before with cracks but not something this large (photo attached).

[mahyongg]

You could also just put in a layer of ABS if you get some, sold for example in RC model building supply shops, in varying thicknesses. i have done a similar repair successfully to a viper, bottom removed, was cracked and brittle, in about basketball size. filled up the voids w/ filled (cotton flour & colooidal silica) gflex, then added the abs layer on top. abs was feathered on the edges, overlapping the also feathered edges of the boats abs layer. after curing, everything covered with another layer of gflex to add some protection for the abs and it works. no edges for rocks to hang up on, so it should be hanging in there for a while..

Here's the repair, check the rest of the images too, if you like!

http://www.ipernity.com/doc/mahyongg/8424925" onclick="window.open(this.href);return false;

Cheers,

Jan

[boatbuster]

That's a beautiful repair. Did you actually glue the ABS to the inner layer using Gflex? In the past I have used Plumber's Goop to attach ABS plates but I have not done it as smooth layer like you did.

You could also just put in a layer of ABS if you get some, sold for example in RC model building supply shops, in varying thicknesses. i have done a similar repair successfully to a viper, bottom removed, was cracked and brittle, in about basketball size. filled up the voids w/ filled (cotton flour & colooidal silica) gflex, then added the abs layer on top. abs was feathered on the edges, overlapping the also feathered edges of the boats abs layer. after curing, everything covered with another layer of gflex to add some protection for the abs and it works. no edges for rocks to hang up on, so it should be hanging in there for a while..

Here's the repair, check the rest of the images too, if you like!

http://www.ipernity.com/doc/mahyongg/8424925" onclick="window.open(this.href);return false;

Cheers,

Jan

[mahyongg]

Yes, I did glue the ABS to the inner foam core with GFlex. Since most of it at that point was replaced with Gflex anyways, and it sticks to ABS really well. I think I roughened it up a little, too, to create some more surface nooks & crannies for the G to tie into. ;D

I figured that what destroys repairs on hulls is usually rocks scraping an edge loose and then popping off the repair by shear force, which you can prevent with a smooth layer and set-in repair... so far, my theory has worked out, although that viper doesn't see the water very often any more... ;D