Pre-Finish Strategy? – Viewer Question
This Viewer Question comes from Jeremy. He writes:
I am about to get started on a really functional project – bookcases made out of MDF. Because they are just for my study, they don’t have to be a work of art. The main point is to get my books out of the 40 or so packing cases that they currently inhabit! I propose to paint the bookcases white. I will probably use a nitrocellulose lacquer and apply it with a spray gun to get a high gloss finish. The last time I did something like this, I did the whole glue up first and then spray-painted the assembled piece. That worked okay but it meant that there was some quite tricky finishing of the inside surfaces and it was difficult to avoid runs on the back and inside faces. This time I was thinking of pre-finishing the uprights, shelves and back before assembly. I would do one final finish coat after assembly to hide any stuff ups!
Now for the question: should I pre-finish the pieces when I have them cut to the final sizes but before routing the rebates and dadoes or rout the rebates and dadoes and then do the pre-finishing? If you think the dadoes and rebates should be cut first, I suppose I should mask them when spraying so that the lacquer does not get in the way of a strong glue joint when I come to assembly. Or could I just glue up the painted pieces using epoxy? If you think the pre-finishing should happen first, should I mask where I am going to rout the rebates and dadoes or could I do the routing through the pre-finish?
Look forward to your answer and thanks for all the great information and entertainment you put out.
And here was my reply
Hey Jeremy. Very good questions. I confronted this issue just recently with my steamer trunk I was working on. You can view the video here. First off, I would not depend on epoxy. There is nothing wrong with that method, but your joints simply won’t be as tight if you do it that way. So I would recommend finishing only after you have the joinery all cut. If you finish first, then rout your joinery, it is very likely that you will scratch the newly finished surface.
So, how to mask the joints? Well, you could simply mask the joints using the tape method. This works great. But in some areas, it can be tricky and/or time consuming. So here’s what I would do. I would partially assemble the case. Assemble everything but the back panel. Then lay the bookcase on some sawhorses. Now, without the back in place, you can finish the inside of the case rather easily. All the joints will be masked simply because the case is all dry clamped together. Now you might have to tape off the rabbet for the back panel, but thats easy enough to do. So its not quite as easy as spraying parts when their flat, but it should be easy enough to get your gun into the tight places because of the lack of a back panel. Then you can just spray the back panel separately. I would also recommend waiting till each coat dries, then loosen the clamps and partially knock the joints apart. This will help prevent the case being “welded” together by the lacquer.
Once the process is done, I would just leave the inside alone. If you try to spray again after the backpanel is on, you will definitely get that annoying overspray that will ruin your nice new finish. Anyway, this is the method that works for me. Hope it helps.
Anyone else have some helpful advice for Jeremy?
Safety Week in Review
As the second annual Woodworker’s Safety Week comes to a close, I am once again amazed at the strength of this community. There were so many blog posts and videos that I just couldn’t keep up. I know I’ll be spending this weekend going back through all the content so I don’t miss anything. I would like to thank all the bloggers who participated as well as our friends Popular Woodworking and Fine Woodworking who made an effort to promote shop safety this week.
As you know, we had some crazy stories this year of injuries and disasters that are truly a woodworker’s worst nightmare. Now I certainly didn’t want to scare anyone with these graphic depictions because fear is a bad thing in the workshop. But awareness and respect are things we can never have enough of. So by seeing the reality of these disastrous situations, my hope is that it will raise your awareness and make you realize that these things can happen to anyone at any time. The other half of the lesson is that these things are completely preventable. And this is really the heart and soul of Woodworker’s Safety Week: the community sharing advice and experiences in an effort to promote shop safety.
So again, thanks to all who participated and took the time to read the posts, watch the videos, and comment on the blogs. Stay safe in the workshop my friends and have a great weekend!
88 – Safety Q&A
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I received a number of great questions for Safety Week and this video covers three of them. The first question concerns running small pieces over the tablesaw and router. The second question is about the proper installation and safe use of a dado blade. The final question concerns the disposal of chemicals and hazardous waste in the shop. An important link I mention in the video is Earth911.com, where you can find your local hazardous waste recycling and disposal centers.
This is definitely more of a conversational episode so you’ve been warned. :) Below is a link to the GRR-Ripper push block.
87 – Dust In Time
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The most common topic request for Safety Week was dust and respirators. So here’s a quick review of the dust and fumes that can make our lives miserable in the shop, and why we need respirators for pro-active protection. And below you will find a links to the exact respirator setup I like to use: the 3m 7500 Series.
The link below is for large, but you can select a different size here: Small, Medium, Large. And don’t forget the upgraded pink filters and the special adapter.
Check it Out!
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