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MG MGA - Floorboard fitting selant

A friend of mine is about to fit new floorboards. What are the current thoughts regarding the best product to seal the gap between floorboard and supporting rails?

Regards...JB
John Bray

Hi John

I'm just about to do the same and was planning to use a black gutter sealant. Bob West suggests that you should definitely not use a sealant that sets.

John
John Francis

I recently asked my chemist brother-in-law, formerly of the paint and mastics division of Rohm & Haas, this very question. He suggested either a black butyl rubber caulk or a silicon based caulk, neither of which would dry and crack or permanently bond the floorboards and rails. He cautioned that asphalt-based formulations may dry and crack with time, trapping moisture. At least here in the US, some older gutter sealants are still asphalt based.

Cheers,
Ken
Ken Korey

I would just get some black RTV gasket maker, and use plenty of anti-sieze on the floorboard screws.
Del Rawlins

I don't remember what I used, but the floorboards most likely will not need to be removed in what remains of my lifetime so I'm not sweating it.

Ed Bell

When I installed my new floorboards in 1977 I used Paintable Siliconized Latex Caulk, 35 year warrantee for outdoor use. If you caulk underneath and all around to fill the side gaps, it likely takes two 10-oz tubes. Do a good job with wood preservative, so the plywood will last as long as the caulking. Available at Ace Hardware, Home Depot, etc:

http://www.acehardware.com/product/index.jsp?productId=1276947

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?&productId=100658163

I put the car back in service in late 1986, have driven it 230,000 miles since then in all kinds of weather, lots of rain and snow, even salt laden mud in Alaska. From underneath it looks like the day it was installed, never been touched. Inside where the carpet has been wet fairly often (and holds moisture for a long time) the caulk released from edge of the plywood in a few places, but the plywood is well pickled so no rot there. In July 2008 (22 years on) I cleaned it up inside, repainted the frame where accessible, and re-caulked it before installing new carpet (3rd time). In short, PSLC is good stuff (and cheap too).
Barney Gaylord

I just bolted them on; no sealant. I don't see the need. I have removed them a couple of times during the last 12 years. No deterioration to the wood nor rails.

Steve
Steve Gyles

Hi John

I've always used 'Dum Dum' as long as it's warmed roll it out like plastercine and 'thumb into place around the floorboard rails, does not set.
I believe it should be available from any good Motor Factor or Moss, etc.
Mark
Mark Dollimore

I used something called "Peel a Seal" I got it at Home Depot in a caulking tube and it seems to work quite well, water proof airtite silicone seal that peels off fairly easily and allows the floorboards to be removed without damaging them. The only drawback could be it has to be replaced if you remove the floorboard for any reason.
John Nelson Burnsville MN
J E NELSON

John

I had another chat with Bob West on Saturday and he now uses a non setting windscreen sealant made by Tex. I couldn't locate this but was recommended to another brand made by Ashead Ratcliffe in Belper. Went to my local Autoglass centre and they gave me two tubes of Ashhead's Arbomast Autograde windscreen sealant, for nothing! It is used on old windscreens with rubber seals and does not set. Looks good stuff and overnight has not set on a test piece.
John
John Francis

I intend to use black polyurethane seam sealant - any thoughts?
Chris Bond

I used Mono housing caulk, applied on the underside after fitting the boards (no caulk in the joint itself)
Art Pearse

Thank you all for your comments and useful advice. I will pass the information on.

Never ceases to amaze me how good and helpful this forum is.

Regards...John
John Bray

This thread was discussed between 28/01/2010 and 01/02/2010

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