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MG MGB Technical - Tar insulation in floor pans

I've searched the archives for this and can't find an answer, so....

I've just replaced my sills and floors. It is my plan to do the waxoyl treatment on the inside of the sills, but the floor pan creates an interesting problem. The originals had a thick tar-like substance that appeared to be poured onto the floor pan. Moss, Vicky Brit, et al sell a "sound deadening kit" that appears to be die-cut material which lies in the bottom of the pan. The restoration book I have, "Porter"
mentions taking it out to prevent welding fires, however doesn't (or I can't find) mention what to replace it with. Was the original just hot poured tar? What are some good modern alternatives to tar? Pick-up truck bedliner comes to mind. It's going to be completely hidden and this is NEVER going to be a concours car, so originality is not an issue. What works to keep down noise, heat and rust?
Thanks in advance.
TDH
T. D. Howard

In the past I have bought sheets of self-adhesive material. This looks like tar, maybe that is what you are talking about. I would suggest trying asking around either body shops or GOOD parts shops, ones that sell to the trade would be good.
Cecil Kimber

TD

Paint the floor area with POR-15 following the directions for surface preparation. Then you can choose the material that provides the best sound and heat insulation without worrying about corrosion due to moisture intrusion.

I once did a 35 ft school bus and uses a foam-lead-foam sound shield material that was VERY effective in cutting interior noise. Have no idea what the material was as this was 30+ years ago.

FWIW

Larry
Larry Hallanger

The original floor covering or mastic was not poured, it was die cut sheets. I'm sure there was tar in the sheets. I've found the front of the left side floor does heat up from the exhaust and over time seem to melt.

I'm considering getting the original Dynamat for my floor covering, but I'm still working on the sills. Would like to hear more about other ideas.
Richard Stinchcomb

Hello TD,

I'm in the very slow process of removing the original stuff, which seems to me to be pre cut sheets. Moss (UK, London) sells a replacement pre cut kit, which looks like the original stuff. I my case the original stuff was placed on the floor (gray painted) and the sound deadening has been painted red (which was the original color). To my surprise the floor was in pretty good condition underneath the sound deadening kit.


Tips are welcome to easy remove the old stuff!

Eric
E. van den Berg

Thanks guys,
I'd still like to find a cheaper way to deaden noise and insulate from heat without causing corrosion,the "sound deadening kit" from Victoria British is $70. The illustration shows it being die cut as original. I figured something could be poured or painted into the low places on the new floor pan to achieve the same look and effect.

To take the old stuff off, I used an old 1 inch (2.5 cm) wood chisel. I used a hammer to sort of "push" it along and the stuff chipped out in large chunks. 'course I did this while it was still very cool here and the tar remained solid, if its warm the mastic will be more stubborn.
That being said, the old tar was the only thing holding most of the floor together, literally.
When I cut out my pans with the reciprocating saw the vibration loosened a great deal of the old tar.

TDHoward

T.D. You can purchase adhesive backed damping material from McMaster-Carr and cut to fit. $14.62 plus shipping per roll 32" x 54" P/N 9709 T19. you will need to cut to size but it beats Moss et al. price to heck and gone. www.mcmaster.com
Bill Taylor

I had to remove that stuff from the floor of my early 70's GT V8 conversion. I used an air hammer with a chisel tip on it. Be careful or you will punch through the floorboards. The chisel takes most of the stuff off but there is still some left there, I used a wirewheel to remove the last of the stuff.
Robert

To add to my earlier post. My 64 B came with rubber floor mats with a jute type backing. The front two had snaps and the rear pair had holes to mount where the fitting bolts for the seat runners are. You can guess what happened when the jute absorbed water. On rebuild, I plan to POR 15 and then use McMaster material cut to fit. Kim DeB used truck bed liner to seal her floors and has posted pictures before on her work.
Bill Taylor

To remove that stuff from the floor of my 69 roadster I used a heat gun. It softened it and I peeled it right off with no problem.
Dana Wilson

i looked at the mcmaster carr website.help.where do you find that material. i have clicked on everything i can think of. thanks.
todd wyatt

found it.apologies.
todd wyatt

I second Dana's method. I just finished my second adventure in this area.(can't believe I'm doing it again). The heat gun and a putty knife works great. Just be patient and let the heat soften the material.
Dan H.
Dan Hanson

Another idea in the other direction is the use of dry ice. Makes the mastic very brittle when hit with a hammer.
Richard Stinchcomb

Heat guns are a worthwhile investment and you can get a decent "two-car garage mechanic/restorer" quality unit from Harbor Freight. You can use them for removal of many other adhesive bonded items, from bumperstickers to other sorts of mastics such as sound deadening and even undercoating. They provide enough heat to loosen adhesives, but usually not enough to start a fire (as opposed to propane torches which I have seen some folks try to use).
Bob Muenchausen

Two Words: 10-Mil Bitchethane ( 6 inch window flash rolls with side by each stripping or 3 x 75 "Ice Gaurd" roll if you wanna do the whole car). I covered nearly every square inch of the interior cockpit sides top, floor, doors ( inside and as moisture barrier under door trim panel), package tray, arches,boot, and fender splash. Peel and stick, then conform with hair dryer heat. Sound deadening was phenom. We have some archive testimonials late last year I believe on this.
vem myers

I used the heat sheild and sound deadener

Vic Brit -- 15-027

shinny side down.
glg

This thread was discussed between 17/06/2003 and 19/06/2003

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