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Mopping Compound

PostPosted: Thu Aug 30, 2018 1:59 am
by vincereynard
What is a recommended compond / technique for cutting / blending new paintwork into existing please?

Products available in the UK.

Re: Mopping Compound

PostPosted: Thu Aug 30, 2018 6:49 am
by elanfan1
Insomnia?

Re: Mopping Compound

PostPosted: Thu Aug 30, 2018 11:22 am
by elansprint
Vince Grizzly did a post about 3M products a while back have a search
Ian

Re: Mopping Compound

PostPosted: Sat Sep 01, 2018 6:24 pm
by Lotus14S2
Just to educate we of the colonies; could you please explain what mopping compound is?

Thank you and regards,
Tim
Auburn, California
1963 S1 Elan
1962 S2 Elite
and others

Re: Mopping Compound

PostPosted: Sat Sep 01, 2018 6:47 pm
by mbell
Probably referred to as cutting compound over here.

Re: Mopping Compound

PostPosted: Sun Sep 02, 2018 9:12 am
by Spyder fan
Unless it's a large area I personally would just T Cut and lots of elbow grease/time.

I recently had a few small scrapes on my VW Golf, which I fixed with a colour match spray and lacquer, a bit of patience and lots of clean cloths applying and removing T cut and the repairs are not visible.

Mopping with a machine takes practice and it's easy to mess up.

Re: Mopping Compound

PostPosted: Sun Sep 02, 2018 10:46 am
by elanfan1
So who scraped it then Al? Must have been a rogue driver eh? 8)

Re: Mopping Compound

PostPosted: Sun Sep 02, 2018 11:04 am
by Spyder fan
a scrape appeared on the n/s rear wheel arch late last year when I was forced to park on the road during building works at the house, no doubt caused by some dimwit who practices touch parking, the scratches and ding were at the height you would expect another cars bumper to be. When I looked at the regular cars that park in our street they all had dings to the leading corners of their bumpers. I also got a nice scrape to the centre of the rear bumper when I was parked on my own driveway earlier this year. One of the neighbours decided to use the drive as a turning point and managed to wedge the corner of their rear bumper against the centre of mine. I actually saw that happen, so negotiated the cost of paint and materials to fix it.

This sort of thing seems to happen all the time, not just to me, I try not to get uptight about it, but I do like to look after my cars and keep them smart looking.

Re: Mopping Compound

PostPosted: Mon Sep 03, 2018 1:39 pm
by derek uk
Blending the colour is done before the clearcoat if that is being used. Once the clear coat is on you will only be compounding that which will have no effect on the colour underneath. Best to do a complete panel and if the panter is any good he will do his best to shade off the colour to where it meets the next panel, say a wing to a door. Not easy even if you are using cellulose with no clearcoat. Trying to merge new and old paint on an old panel is virtually impossible but you might be able to freshen the old paint with compound to at least get it near its original shade before adding new. Basically, you are the mercy of the painter so pick a good one.

Re: Mopping Compound

PostPosted: Tue Sep 04, 2018 10:38 am
by Grizzly
Be carfull using T-Cut origanal on modern clear coats, especally where it's been blended..... The Ammonia makes the fresh clear milky if your not careful.

Vince, i know your car is yellow but i don't know if thats direct gloss or clear/base...... my advice would be take it back to the guy who did the job (if possible).... if you have origanal paint and some one has blended modern direct gloss over it you could well have issues with edging up which would only get worse the more you polish. Blending isn't rocket science just as long as the guy that did the work was carfull with his prep, used a good colour match and used matching materials.

Re: Mopping Compound

PostPosted: Tue Sep 04, 2018 1:00 pm
by JonB
When I saw the car on Sunday Vince told me it was painted with cellulose so no clear coat. I must say, he did a really good job matching the colour. It looks like it only needs cutting in and polishing to finish.

Re: Mopping Compound

PostPosted: Tue Sep 04, 2018 1:29 pm
by Grizzly
If it's celulose t-cut or a fine brasing compound by hand i'm afraid........ you could use a machine polisher but Yellow Cellulose doesn't have alot of pigment in it (it's a bit transparent) so tends to be on the thin side which makes it very easy to burn.

If it's been applied old school you shouldn't be doing any real denibing, i'd usally give it a quick go over with a 3M 3000 trizact pad (do it with plenty of water on a da sander at low speed, hardly takes anything off but even so don't go near the edges) then finish by hand (origanal T-cut).

Re: Mopping Compound

PostPosted: Tue Sep 04, 2018 9:46 pm
by vincereynard
Thanks for the replies.

After a bit of useless faffing trying to mix a match myself, I found a local paint shop than would mix up a big aerosol with paint from a "recipe" created by a spectrophotometer (?)

As Jon stated it is virtually a perfect match, (time will tell how perfect).

I "blended" the join with a sheet of 2000 paper folded into a pad - very gently, loads of hand soap. Then manual yellow Tcut followed by some very mild original . So far it looks good.

I had forgot how long celli takes to fully harden - its been a week and I'm still not confident in bolting the boot hinges back on.