# Best finish for construction grade lumber?



## ynathans (Sep 12, 2013)

Hi,
I am nearly finished with this bunkbed build for my boys: http://woodgears.ca/bed/bunk_bed/plans.html.

I used construction grade lumber but milled it all with my jointer and planer. With all the time I have into the project I am hoping to finish it real nice.

I have heard that construction grade lumber can be hard to finish nicely but I am looking for input on how to finish it, including how much to sand (up to what grit?), the best finish type, in between coats treatment, and poly type/coats.

Thanks in advance.

Nathan


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## GregD (Oct 24, 2009)

This project is from framing lumber finished with clear poly. I use Minwax fast drying polyurethane and apply with a good quality brush.

Applying stain is a whole other skill. I am not good at it. And soft woods are usually prone to blotching. Charles Neil's web site offers his special blotch control formula.

Are you going to stain?


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## ChefHDAN (Aug 7, 2010)

Nathan, are you looking to go for light tones or dark tones? Your best first step is going to be playing with some of your stock left overs to test the finishes. I don't sand much over 180 for most stuff, 220 tops if it's a really nice grain or hardwood. Since the wood you're working with is soft and pretty wide grained, you'll want to use conditioners before any staining, but since it's bunk beds for boys, I'd be looking to go simple for the finish with a tinted Danish oil, 3 coats, at least a week of drying and then an oil based poly over that to make it almost kid proof.


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## ynathans (Sep 12, 2013)

Hey guys,

Thanks for the replies. To answer the question: the wife was hoping for a darker stain but if the consensus is that dark would not go well we would go lighter too.

I meant to ask about using wood conditioner first since I know the wood is prone to blotching. Would you guys recommend that as a first step?

Thanks,

Nathan


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## ChefHDAN (Aug 7, 2010)

Nathan, I've had good luck using dye for softer woods, and have like the results, check out mark's video here, http://www.thewoodwhisperer.com/videos/you-and-dye/ to learn a bit about them. I used this, http://www.woodcraft.com/Product/2000760/2355/Homestead-Transfast-Dye-Powder-Dark-Mission-Brown.aspx on moldings, ply, handrails and some hard woods and got really good results without using any conditioners. The key thing is to do samples first before you commit to the whole project.


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## ynathans (Sep 12, 2013)

@ChefHDAN-thanks, I might order some of that and give it a shot.

@GregD: I like the way that came out. Do the pics show the poly already applied? It looks like it is, but the post seemed to say it hadn't been applied yet. Also-did you just sand and apply? Any conditioner first?


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## Lifesaver2000 (Nov 17, 2009)

If you would like another example of construction lumber with a clear finish, I used the same Minwax poly Greg mentioned over southern yellow pine in this project:



It has been in use over a year with no signs of wear. I simply sanded to 150 grit and then sprayed the poly using HVLP. No preconditioner or stain or anything else.


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## TiggerWood (Jan 1, 2014)

I can't stand the scratch pattern left from lower grit sand paper. If it wasn't for staining, I would sand to 400 grit.


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## GregD (Oct 24, 2009)

My bad. I jumped the gun on that and took pics before I slathered on the poly on that one. So use Lifesaver's project as a better reference.

AFAIK, conditioner is to control blotching while staining. I have not seen the need for it when applying poly to unstained wood. However, if you have significant end grain it will need to be sanded 1 or 2 grits higher if you want it the same shade as everything else - otherwise it will soak up a lot of finish and darken considerably. I have also heard that dyes are easier, as ChefHDan suggests.

But do remember that every stage of the building/finishing process requires at least a bit of practice. So if you have your heart set on a nice finish on your bunk beds I recommend that you first knock together something with of the same material and go through the entire finishing process on that piece as if it were an important project. For me, the second time through a new process usually works out much better than the first time through. And yes, going through the process for the first time will take some materials and a lot of time and attention. But you will learn a lot.


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## bondogaposis (Dec 18, 2011)

Simplify your life; sand to 180 grit, skip the stain, use a wiping varnish, several coats, lightly sanding w/ 400 git between coats, after final coat rub down w/ brown paper bag and wax.


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