HuckleberryTinn
Member
As I was poking around in my boat today in between rainstorms I noticed a few Styrofoam pellets which I traced to a nearby seat. After a little investigation I realized that what little foam flotation this boat has is made up entirely of expanded Styrofoam. I started looking at options to replace the existing foam and stumbled onto onto a paper that was written buy a Coast Guard representative. It's a very interesting paper that compares aluminum and fiberglass boat construction. The part that immediately caught my eye was about foam recommendations. Here is an excerpt from that section:
Specific to aluminum boats, flotation must be resilient foam such as solid or beaded EPE or EPP rather than pour in place two part polyurethane. Polyurethane is relatively brittle and the foam against an aluminum shell will crumble as it flexes, leaving a faying surface that absorbs water (and gasoline) and promotes internal corrosion. Polyurethane also is highly flammable, produces toxic fumes in a fire, and must be removed prior to any welding. (Polyurethane can be removed by pressure washing.) It also gives off fumes that can cause respiratory distress to sensitized individuals when it is poured in for repair. Unfortunately, EPE and EPP cannot be blown in place and must be purchased as sheets, stacked and cut to fit. This is a substantial increase in initial cost, but it prevents corrosion and allows the foam to be removed intact for repairs and put back in.
And here is the link to the paper: https://www.sname.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=dbf103fb-4814-f523-4f53-fe15cf989212
I never considered that foam might absorb and retain fuel. That seems a little concerning to me. The paper also talks about other subjects such as corrosion and rust. I have stumbled on a cheap source of expanded polypropylene(EPP) on craigslist and was wondering if this could be used for flotation.
I just wanted to put this out there in case any of you we're interested in some technical reading concerning our hobby.
Specific to aluminum boats, flotation must be resilient foam such as solid or beaded EPE or EPP rather than pour in place two part polyurethane. Polyurethane is relatively brittle and the foam against an aluminum shell will crumble as it flexes, leaving a faying surface that absorbs water (and gasoline) and promotes internal corrosion. Polyurethane also is highly flammable, produces toxic fumes in a fire, and must be removed prior to any welding. (Polyurethane can be removed by pressure washing.) It also gives off fumes that can cause respiratory distress to sensitized individuals when it is poured in for repair. Unfortunately, EPE and EPP cannot be blown in place and must be purchased as sheets, stacked and cut to fit. This is a substantial increase in initial cost, but it prevents corrosion and allows the foam to be removed intact for repairs and put back in.
And here is the link to the paper: https://www.sname.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=dbf103fb-4814-f523-4f53-fe15cf989212
I never considered that foam might absorb and retain fuel. That seems a little concerning to me. The paper also talks about other subjects such as corrosion and rust. I have stumbled on a cheap source of expanded polypropylene(EPP) on craigslist and was wondering if this could be used for flotation.
I just wanted to put this out there in case any of you we're interested in some technical reading concerning our hobby.