A friend just bought a used Tornado mast for use on a project boat. Turns out a previous owner had filled the mast with expanding foam! Probably in an effort to make the mast waterproof the easy way instead of the proper way. Too bad he did not notice before he bought the stick.
Now we are looking for ways to remove the foam. It looks like regular construction grade foam, like you use when installing new windows e.g. at home. Suggestions on what chemicals might eat such foam. Acetone? Benzen? HCl?

Doesn't gasoline eat most foams... it is all expensive but try it out.

yup - acetone. I believe gasoline/petrol may do the same (but leave a bit of a smell). Regardless, that's going to be a gooey mess.

Dig some of the foam out and try different solvents in a can or cup before pouring a whole lot of anything down the inside of the mast. That foam may be a lot more chemical resistant than you think. Any way you slice it you are going to have a very time consuming caustic mess. You might want to try and remove as much of the foam as possible by mechanical means before resorting to chemicals.

Regards,
Bob

Good point...not to mention explosive...imagine napalm.

Do you know anyone who has a 4000psi Water pressure cleaner?...put the Zero degree tip on it and you probably could get more of it out than any other way...more than using chemicals which will leave a thick goo all over the sidewall that you will never get out, That goo will greatly increase the weight of the mast.

With the pressure cleaner you will eat right thru it and eventually blow it right out the other end...if it can strip the flesh right to the bone on a human it will annihilate the foam.

Regards,
Bob

Rolf,

Is it DIY foam or is it Epoxy foam ?

If it's the expanding DIY foam, that can dry as hard as nails (but the pressure washer might do it)

If it's poly foam than swearing at it might remove it <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Epoxy foam could be a major PITA !

Can it be dipped in a tank of acid. Like at a chrome plating shop, or something of that nature? Or is it composite.

Pressure washer is a good idea too. The spinner tips will rip through boots, and your foot like its butter. Kind like the 0 degree tip, but it rotates.

The mast in it's current form is 9.2m long, and the top is sealed. I think we will have to become creative if we are to remove the foam by mechanical means.

The foam is definately some form of DIY foam, but how they got it to the top beats me!

Perhaps cutting the top off, somehow removing as much as possible of the foam and pushing a injection valve connected to a strong pressure washer trough it is the best bet? 4000psi.. jeez!

Will remove some foam and do the gasoline test tonight. Owner smokes, so we will be careful with the napalm trick. <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

Rolf, I like the pressure washer idea, but you might also try a "snake" for cleaning drains. You attach it to an electric drill and feed it into what you want to clean out. We used one to clean out an old well that was blocked with tree roots.

More brainstorming here:

1) Use a drilling rig that is used to drill a well.


2) I'm thinking of a sewer drain razor cleaner. I believe that there are some that are spring loaded and compliant to conform to the size of the drain pipe.

I wonder if turned slowly enough if it could conform to the varying diameter of an oval mast. I also wonder if the rivets will allow the tool to pass.

If this method was used, I would go very slowly while trying not to get snagged on rivets.

3) Apply a hot iron to a sample of the foam to see if it looses it's adhesion and shrinks. If so, perhaps an electric charge could be used at each end of the mast to send a current from one end to the other to heat the entire mast evenly.

A variable voltage generator as used by home made hot wire foam cutters would probably work well.

Then perhaps you could press the entire core out from the top to the bottom, while it is hot and in a state of surface melt.

I'm curious if you have an estimate of how much all that foam weighs.

GARY

Brian,

we might get a hole trough the foam with a "snake", but since the crossection is pear shaped there will be a lot of remains. So chemicals or some other post procedure followup would be neccesary.

Gary, you are a dangerous man! <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" /> I tought the mix of gasoline and foam (napalm) sounded dangerous, but your idea of using DC current to heat the mast is really nasty <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />
I dont think we will try that. I imagine the heat needed would be more than what's good for the mast. I dont know tough..

We are going to rebuild the mast, so we will drill and remove all rivets. The razor idea might work. I dont think we will get enough tension on a 9 meter long hot-wire to cut well. Would need a thick wire to stop it from melting becouse of the current needed. Good ideas tough!

I don't think gasoline is appropriate. It often contains very unhealthy additives. Many foams dissolve quite readily with acetone, especially styrofoam. However, acetone is very volitile and evaporates easily. Try MEK, methyl ethyl ketone (butanone). It is less volitile and is very similar to acetone with respect to dissolving foams. If it works you won't need much. A game that chemistry teachers play with styrofoam is to have students guess how many foam packing "peanuts" will dissolve in 50 mL of acetone. It holds more than 100! When the dissolved foam/MEK gets thick change to fresh solvent. MEK is cheap and available at Home Depot type stores.

And as to using benzene, NO! Carcinogenic. Seriously bad shite.
As to HCL, NO! It will eat the aluminum and is doubtful on the foam.
As to "caustic", poor choice of words. This often relates to bases or lye products, not ketone solvents. Otherwise it relates to eating living tissue and actone or MEK won't do this either.

P.S. Don't confuse MEK with MEK peroxide catalyst used with epoxy resins.

You mean "polyester resins".

Rolf

DIY foam comes in 2 variaties, latex and polyurethane. Acetone or gasoline will probably dissolve both. The problem is unless you use a lot of solvent, there will be a lot of sticky residue.

One is solution is to use the commerical foam cleaner as a final rinse. The commercial foam cleaner is used to clean the foam dispensing guns and are mixture of nasty chemicals.

I once had to do this for work when we had to remove a foam liner from 20 ft long tube. We were able to determine that a mixture of gasoline and liquid detergent would clean it perfectly. However this is real clase to napalm.

We ended up using a machine made to clean air conditioning ducts with a bronze brush instead of the soft nylon brushes they normally use.

WOW David, You must be a chemical engineer! It was over my head. <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" />

Thanks for the info on MEK. I will try it. Less volitile is very important during August in Houston.

If you scratch or gouge the inside of the mast with metal removal tools it may fail at those points.

I would try hammering sharpened plastic storm water pipes through the mast, repeatedly removing and punching out the foam core that will fill the pipe. After mechanically removing as much material as possible I would try high pressure water but I suspect the foam in the middle wont be removed by this method. In that case, with the mast vertical, sealed and with most of the foam already removed mechanically I would fill it with the cheapest solvent that has been proven to dissolve the foam, leave sit for 24 hours the drain it and blast it out with water.

This job will make a huge mess, especially the solvent aspect, I would consider leaving the foam if the performance impact is negligiable.

Interesting problem to solve using tooling available at home.

Darryn
Mozzy
1782

Darryn with a 2700 psi water pressure cleaner with a zero degree tip you can etch your name in concrete block... with a 3500 psi or 4000psi unit you will blow that foam into next week.

Regards,
Bob

And presumably the mast!