Questions about building with foam

[tlsallada]

Has anyone tried using one of those 'multitools' with the vibrating blade to cut 2 inch foam. I already have one of those and don't really want to invest in a hot knife tool that I'll probably only use for this project.

[GPW]

A good SHARP handsaw cuts foam just fine ... jigsaw for curves... You could try out that vibrating tool and let us know how it worked for you ...

[KCStudly]

I have used a thin straight blade large steak knife (or small boning knife, not sure which), one of those cheap extending snap blade utility knives, the table saw and the router, all to good effect. The router is by far the messiest, the table saw is not too bad, and the knives are very clean. Haven't had a need for a hot knife yet, but I suppose it would have been handy at times.

Don't convince yourself that the tool you don't have will solve any problems you may perceive, it might not work out the way you imagine. Use the tools that you have to your advantage and get the job done. If you run into a road block, then consider other options when the time comes.

p.s. Regardless of the tool, invest in a respirator first. You will invariably be sanding or using power tools on foam, and will likely be kicking up some wood sawdust, too.

[ghcoe]

Has anyone tried using one of those 'multitools' with the vibrating blade to cut 2 inch foam. I already have one of those and don't really want to invest in a hot knife tool that I'll probably only use for this project.

I used one a bit. Have to be real carful while cutting because it will get away from you real quick. I don't think it would be real practical for most applications in fomie building though. I had to use mine when the Great Stuff foamed up WAY to much when I was gluing the body to the floor. Had to wait for the glue to dry and then used that tool to zip the body back off the floor. Worked great for that.

I love the hot wire. Once you use a hot wire for cutting it is really hard to use anything else. No mess and it leaves a nice hardened surface. Just make sure you have plenty of ventilation.

[iregan]

Hot wire is by far the best in my opinion, but the "other" traditional tool for foam is a good old kitchen electric carving knife, surfboarders have been using those since day one of foam building. I would imagine a normal knife for carving your roast etc would work fine, as might a drywall saw.
Regan

[GPW]

You guys do know how to make a simple Hot wire foam cutting bow huh ? It’s cheap and easy !!! And that allows “Gravity cutting” , which is very accurate .

[dales133]

Dale , I know this may sound Crazy , but what about that double stick tape the cargo trailer folk use to stick Al to Steel ... Supposed to be VERY Sticky... and would hold varnished surfaces with a little bit of flexibility too ... (like everything else , best “test” that idea first)

I havnt considered double sided tape but I used some of the realy good stuff the otherday and it's supper strong.
Only problem is you only get one shot at lining it up.
My bulkheads carpeted one side so I'd need to mask it up with polyurethane adhesive.
KC I contemplated sanding the poly off but I recon the potential to damage or unevenly sand is to high....I have left the wall tops raw timber as are the spas so I'll used tb3 there witch will be strong as

I have tried to always keep raw wood where ever I plan to glue, or mask the area and sand back the poly and stain before gluing.

[GPW]

Just thinking .... Gluing pre-finished panels together, a different “constructiion” adhesive than the usual T2 might work as well allowing for ALL the wood bits to be completely sealed.
And then , This isn’t woodworking ... this is “Foamworking” ... wood used merely for incidental framing/reinforcement .. or ideally , not at all eh ?

[daveesl77]

While this first build of mine is a sort-of hybrid, the more I see what you foamie folks have done and are doing, the more I am absolutely certain that if and when I build another it will be a foamie. I have a hard time seeing ANY negatives to doing a foam build. This is a brilliant concept and makes perfect sense. I now look at mine and the weak points I see are all wood related and with the foam parts I say to myself "oh, that's foam it is fine".

dave

[rowerwet]

Has anyone tried using one of those 'multitools' with the vibrating blade to cut 2 inch foam. I already have one of those and don't really want to invest in a hot knife tool that I'll probably only use for this project.

My cutting tool of choice is a drywall saw, I get the cheap one from Harbor Freight as it is double sided, no need to pull it out and flip it around to clear the cut.
I like it because it isn't very flexible.

[tlsallada]

In my ongoing research I stumbled upon this YouTube video of a test of several different adhesives for foam. I thought I'd share with you all.

https://www.youtube.com/watch?v=rnOegaOKu38

Enjoy!!

[ghcoe]

Hey, we know that person.......

[Mary C]

Might I suggest that you get every cutting tool you have jig saw,kitchen knife,razor, electric knife,etc and try them all at one time try different techniques Like me I have tried them all and found that sometimes different needs dictated a different cutting implement. I have a small saw on a pocket knife it came in handy in little spaces. I did not like the kitchen electric knife, not on this type of foam. The jig saw was the best for me.
Mary C.

[lthomas987]

Mary's comment is spot on. Odds are you'll use them all in the end. The one I didn't get to til I was nearly done but turned out to be great for cutting notces in the edges of things was a putty knife of just under the width I wanted heated over my camp stove. It was a but stinky but I was working outside.