I am going to add foam to my tank........a 22 gallon aluminum sumped tank , and am wondering if it is possible to use any adhesive to hold the foam blocks in place.
The tank has a sending unit and I would like to avoid the foam blocks moving around and fouling / impeding the float.
I will be running E-85 and the foam is supposed to be O.K. with that.
I was wondering if some kind of silicone might work here.
That or maybe using a length of wire and " pinning " the blocks together.
Anyone have any experience in this area ?
Thanks in advance.

I don't think you will find any adhesive that will work in the fuel cell but you could probably build a basket from expanded metal to put around the float. When I put a sender in my cell I removed all the foam and I haven't had any issues from the fuel slosh
Gus

Just make the foam the entire size of the tank and cut the area out for the sender.
Doug

I used the technical expertise and parts from these guys to update my fuel tank. They know tank design theory, foam placement etc. and are very helpful. Great customer service and expertise.

https://www.harmonracingcells.com/

Rick's Tanks built the larger tank using my spec's and they did a great job of baffling it. I get no fuel slosh out the filler neck. Later, I upgraded the inner-workings with the help & guidance of Harmon Racing Cells.

First photo shows internal baffling and a pair of Holley Hydramats with -10 fittings and fuel-submersible rated fuel lines. My 2-speed Fuelabs fuel pump is mounted just outside the tank and up near the top of the tank to protect it from road debris and provide easy access. This set-up provides air free fuel down to the last few ounces of fuel in the tank whether drag racing or on a road course.

Gus, have you seen this stuff? Tim
http://www.ppgaerospace.com/getdoc/11784...nk-Sealant.aspx

https://www.aircraftspruce.com/catalog/appages/ps890.php?clickkey=59208

This stuff is cheaper..
https://www.aircraftspruce.com/catalog/appages/prosealant.php?recfer=12662
you need to mix it correctly but it will stick anything metal to anything it seems, but stinks like hell...until it dries.

Just buy a tubular sending unit.

BINGO !
Not cheap , but better than some of the ideas I had. LOL
http://www.tanksinc.com/index.cfm/page/p...prod/prd346.htm

I heard 3rd hand about people having problems with the foam coming apart and I got scared and pulled my foam out.

I have only seen this on an F-15 that had an internal fuel tank fire...and it flew for years until we figured out what caused the foam to break up.

I would not glue the foam in with any permanent glues. Most foams in our applications, have a limited lifespan. I would not favor what it takes to remove old permanent glue when time comes to replace the foam.

Many Ag airplane also use foam. That said aviation has very struck fuel standards so they can build the foam to resist breaking down.

I have dealt with the ASTM specs for avgas and gasoline, gasoline is actually regulated to a stricter standard than Avgas because so many local emission rules apply to cars and not airplanes. I build a fuel valve for an antique airplane so I did lots of research on the topic. Tim