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Fumbler
21st May 2018, 03:51 PM
Contrary to my better judgement I gave a sand and 1 final coat to a price I'm working on, but I only did one surface, stupid I know, but I have the desired result. However, there is a slight amount of overspray on the sides and has just taken the gloss off the sides and given a slight sandy feel to it. It was sprayed 4 hours ago.

i can either wait til tomorrow then rub back slightly with 0000 steel wool and recoat, but I don't want to mess it up.

so not wanting to mess it up how can I recover from here. How do bring it back to a gloss smooth finish without spraying.

the finish is cabothene clear gloss spray can.

all advice and help would be appreciated.

thank you

Arron
21st May 2018, 06:55 PM
Well, I’d be thinking let’s not make things worse. I wouldn’t be putting any more coats on till I was sure I couldn’t resurrect the current finish. I would leave it for about a week before doing anything.

Finishes like pu have a two stage cure. The first stage is simply solvent evaporation. At the end of that stage the finish may feel dry, but if you start working it you’ll find it’s still quite soft. This stage may take 30 mins or maybe a few hours.

The second stage is a catalytic cure - a much slower chemical reaction. At the end of this stage it’s very much harder. This can take 1 or 2 weeks.

So I’d wait till I was sure the reaction was finished, the product was hard, and then I’d buff off the overspray, and perhaps buff all round.

The one proviso to this is that pu products are typically not as amendable to buffing as other products like lacquer or shellac. You may find when you work on the pu finish you will drag the surface - just your penalty for using pu I’m afraid, but give it a try.

Likewise, if you had used a lacquer then the overspray across the side of the workpiece would probably have melded into the previous finish, or just brushed off.

Isn’t finishing fun!

Cheers
Arron

Fumbler
21st May 2018, 07:41 PM
So 12000 micromesh pad won't do it?

Arron
21st May 2018, 07:49 PM
I can’t see any advantage in 12000 at all.

When buffing lacquer and shellac finishes I do 1200 or 1500 grit paper, then a couple of levels of auto polishing compound. I don’t know what grit the compounds are (the manufacturers carefully avoid revealing this fact) but I doubt they get close to 12000.

The knobbles of overspray are very large compared to 12000 grit, so you are just polishing across their surfaces. To remove the knobbles you need a grit that approximates their diameter, or a simple fraction of it.

safari
21st May 2018, 09:06 PM
Hi fumbler, I don't know if this will help your problems but it might give a clue or two.

https://www.youtube.com/watch?v=96KywJlZ9g4

woodPixel
21st May 2018, 11:29 PM
That video is quite good. My experience is to do 1000 then 2000 grits. Going straight to 2000 makes for a long job and often fails to get the universal flat you'll need for a first class job.

It is also pointless using less than 1000 on CA or PU as it just adds more work. For the papers, I just use Wetndry from the car shop. I've a few 150mm pads from TSPM too... Should probably get more of those....

SOAK the paper! Also, use the pad, never your fingers or hand.

For the water, add in a few drops of dish liquid. On the polish, use Meguiar's SwirlX.

PU polishes fantastically. On a box it is astounding. :) It is quick and easy. As pointed out, however, you do need to wait a full week. There is no rushing that bit :(

woodPixel
21st May 2018, 11:35 PM
Ah yes, Fumbler, for the nibs get a "denibber" from the auto store. Car refinishers use them.

https://www.amazon.com/gp/aw/d/B000RI9GF0/

You DONT need a ROS. A soft block and paper is quick. The soft block is again from the auto store in the finishing and paint area.

Fumbler
22nd May 2018, 04:05 AM
Thanks all, i think i'll do the unthinkable and give it all another light sand with 400 Abranet and then give the entire piece one last coat.

I don't want to have to wait 2 weeks only to find out it doesn't work then have to start from scratch, I'd prefer to balls it up now and then restart.

Its an awkward piece, and definitely not ROS friendly. even though my wife said it looked fine before I did the last coat, me thinks she just wanted it finished so I can help her in the garden by digging up someone else's lazy effort (ie. throw down mulch) so that she can lay some turf.

As Arron said finishing is fun........ Not. I enjoy finishing when it works first go.

Fumbler
22nd May 2018, 04:52 PM
I'd thought and thought, and was as nervous as hell but I'm happy to say, success.

I sander with the multi-tool with 400grit Abranet then wiped with Metho, then 2 goinging over with 0000 steel wool, one coat and bingo. Problem solved. Now to let cure, as I won't be touching them again until it's time to bolt everything together. Hopefully I won't bang or knock them whilst ducking and weaving in the shed.

thanks for all the advice.

the curing rack

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