# Why BLO



## Emery (Jul 2, 2012)

I'm still new at pen turning but have developed a pretty good method of applying a CA finish. I have seen others use BLO between coats of CA. What is the purpose of the BLO?


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## NewLondon88 (Jul 2, 2012)

if you've got a good CA method down, then BLO is evil. It's useless.
It's for the paeons. Ignore it. Throw it in the trash. Look the other way.
You've got a good thing going.. so DON'T MESS WITH IT!!

But for others, it lubricates.. helps start kick the CA and also helps
the paper towel to not stick to the glue. It works for some, not
so well for others. Whatever works for you is the right way.


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## JD Combs Sr (Jul 2, 2012)

Ditto what Charlie said!


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## PenMan1 (Jul 2, 2012)

NewLondon88 said:


> if you've got a good CA method down, then BLO is evil. It's useless.
> It's for the paeons. Ignore it. Throw it in the trash. Look the other way.
> You've got a good thing going.. so DON'T MESS WITH IT!!
> 
> ...



Throw it in your NEIGHBOR's trash. I nearly burned the shop down just cleaning up a BLO spill. Charlie is right! This stuff is evil.


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## NewLondon88 (Jul 2, 2012)

PenMan1 said:


> Throw it in your NEIGHBOR's trash. I nearly burned the shop down just cleaning up a BLO spill.



You're right .. I mis-spoke. I meant to say throw it at your neighbor.
My apologies.


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## its_virgil (Jul 2, 2012)

Emery said:


> I'm still new at pen turning but have developed a pretty good method of applying a CA finish. I have seen others use BLO between coats of CA. What is the purpose of the BLO?


 
Emery,

Your question has been asked several times over. Here is the answer given by a member of another forum.

The answer is from:
Dr. Henk J.M. Verhaar, Principal
ENVIRON Home - ENVIRON Global
Willem Arntszlaan 
the Netherlands 

Q: Does anyone understand how Boiled Linseed Oil and CA glue react to make such a nice finish?

A: Yes. The CA acts as a crosslinker for the BLO - you basically get an
accellerated linseed oil resin matrix with added durability and water
resistance.

(Normally, oxygen generates radicals in the oil which then act as crosslinkers - a much slower reaction, and resulting in a resin with other properties than a CA-crosslinked BLO resin).

BLO by itself cures through exposure to oxygen. Oxygen from the air will oxidize the double bonds in the fatty acid chains of the BLO triglycerides (and remember, all vegetable oils and animal fats consist of triglycerides). These oxidized triglycerides will then attack further double bonds, and attach to them, so that you get a (3D) network of triglyceride molecules. Basically what you get when BLO cures is a natural resin (plastic if
you like). BLO, in contrast to raw linseed oil, contains catalysts (called a
siccatif, usually consisting of heavy metal salts) that considerably speed up the process. BLO cures in hours to days, whereas raw linseed oil needs weeks to months to cure. However, when combining BLO (or raw linseed oil) with CA, a reaction will take place between the CA and the double bonds of the fatty acids. In effect you get a co-polymer resin of CA
and BLO molecules. Since CA is so reactive, this process is much more rapid than BLO curing. The BLO itself is, ideally, completely 'consumed' by  the (excess) CA, so no actual normal BLO curing will take place.

The advantage of CA-BLO over straight CA is that you get a more flexible, less brittle resin than with polymeric CA alone.

I am one of the users of this evil stuff and I really like the finish I get. No, I don't understand the above answer but Henk does know his stuff. I can go with or without boiled linseed oil but I like the finish better using it. So,
my neignhbor is safe. I will keep it in my shop.:biggrin::biggrin:

But, it can be nasty stuff. Do not leave regs soaked with it piled in the shop. It can combust by itself.

I agree that if you have a method that works don't change it. 

Do a good turn daily!
Don


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## PenMan1 (Jul 2, 2012)

Don:
Henk lost me at crosslinker! I've used BLO a time or two, but I sure ain't no crosslinker
Aren't they the ones who dress funny.)


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## its_virgil (Jul 2, 2012)

Andy,
The news is now out. Once you used BLO you are a crosslinker and once a  crosslinker always a crosslinker. Maybe a crosslinker is one who starts a golf game on one course and finishes the game on another one.:biggrin:
Do a good turn daily!
Don



PenMan1 said:


> Don:
> Henk lost me at crosslinker! I've used BLO a time or two, but I sure ain't no crosslinker
> Aren't they the ones who dress funny.)


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## NewLondon88 (Jul 3, 2012)

its_virgil said:


> Andy,
> The news is now out. Once you used BLO you are a crosslinker and once a  crosslinker always a crosslinker.



.. not that there's anything wrong with that..


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## Wildman (Jul 3, 2012)

I tried Russ Fairfield’s directions for finishing with CA & BLO, except applied BLO first. After reading instructions again followed his instructions, did not find much difference.  Did find skipping BLO sped up finishing procedure, so stopped using BLO. 

Cannot say BLO adds or takes anything away from final CA finish in my experience. 

Stopped using CA as a finish and for glue ups.


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## kruzzer (Jul 3, 2012)

I've tried the blo/ca finish in the past and liked the results however in my experience clouds develop in the finish of some pens... maybe one in ten.  I don't know if it was moisture content of the blank but after a couple of re-finishings I stopped using blo and use ca only.   That was a couple of years ago and Ihaven't had the problem since..


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## panamag8or (Sep 27, 2012)

its_virgil said:


> Maybe a crosslinker is one who starts a golf game on one course and finishes the game on another one.:biggrin:



Or hits from one fairway, and ends up on the adjacent fairway... been there, done that. :redface:


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## ed4copies (Sep 27, 2012)

panamag8or said:


> its_virgil said:
> 
> 
> > Maybe a crosslinker is one who starts a golf game on one course and finishes the game on another one.:biggrin:
> ...



What is a fairway?:biggrin::biggrin::biggrin:


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## triw51 (Sep 27, 2012)

its_virgil said:


> Emery said:
> 
> 
> > I'm still new at pen turning but have developed a pretty good method of applying a CA finish. I have seen others use BLO between coats of CA. What is the purpose of the BLO?
> ...


 

I did not know the why it worked so thanks Don for explaining the scientific facts of BLO/CA finish.  I use the BLO/CA finish when I saw a members viedo and when I tried it I got great results.  Nice glossy finish only draw back is you lose the natural feel of wood.  I am open to new ways and ordered some WTF from Ed to give it a try.
So I would have to say my neighbor hood is safe also I'll keep the BLO safely in a locked cabnet.


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## Steve Busey (Sep 27, 2012)

I've had people tell me that BLO helps to "pop the grain", whatever that means.

So to figure out what it means, I turned a cherry cylinder, wiped a coat of BLO on half of it, let it dry, then finished the whole thing (I think I used WTF). the BLO portion had a more vivid contrast in the grain. Nothing fantastic, just a noticeable difference.

So, if I have some wood with nice but fairly bland grain, I might put a coat of BLO over it before finishing, but frankly, that's not very often.

HTH


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## joefrog (Sep 27, 2012)

Steve Busey said:


> I've had people tell me that BLO helps to "pop the grain", whatever that means.
> 
> So to figure out what it means, I turned a cherry cylinder, wiped a coat of BLO on half of it, let it dry, then finished the whole thing (I think I used WTF). the BLO portion had a more vivid contrast in the grain. Nothing fantastic, just a noticeable difference.
> 
> ...



I have some really nice fiddleback maple that I'm going to try it with tonight if I have time.  We'll see!


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## Lenny (Sep 27, 2012)

its_virgil said:


> <snip>Maybe a crosslinker is one who starts a golf game on one course and finishes the game on another one.:biggrin:
> Do a good turn daily!
> Don


 
I ressemble that remark! :biggrin:

I tried the BLO for awhile.... got better results after eliminating it .... which could be just a coincindance, but once something works for me I stick with it. (In the case of CA, sometimes quite literrally!):biggrin:


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## bradh (Sep 27, 2012)

Steve Busey said:


> I've had people tell me that BLO helps to "pop the grain", whatever that means.
> 
> So to figure out what it means, I turned a cherry cylinder, wiped a coat of BLO on half of it, let it dry, then finished the whole thing (I think I used WTF). the BLO portion had a more vivid contrast in the grain. Nothing fantastic, just a noticeable difference.
> 
> ...



"Pop the grain" means getting the grain to be more pronounced. BLO does this through a colour change; you can also get the same effect by sanding ulta-smooth before CA. Read about this on Russ Fairfield's site (at the bottom of the page):
FS-5


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## LagniappeRob (Sep 27, 2012)

Steve Busey said:


> I've had people tell me that BLO helps to "pop the grain", whatever that means.
> 
> So to figure out what it means, I turned a cherry cylinder, wiped a coat of BLO on half of it, let it dry, then finished the whole thing (I think I used WTF).
> 
> ...



I was under the impression (maybe read it somewhere? ) not to use a wax or oil underneath GFWTF.  GFWTF is a water-based hybrid polyurethane (I think) and the wax and oil would prevent the poly from adhering to the wood itself.


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## LagniappeRob (Sep 27, 2012)

Think this is what I read:  The Woodturning Forum - Woodturner's Resource - lessons learned with Woodturner's Finish

Specifically: 


> Update:
> As expected, woodturners finish did not do well over BLO. It was going on great, went through the micromesh beautifully, but when I polished with the mequiars, it lifted right off. I am next going to test letting the BLO cure for a week, and try again. There are just so many woods (burls and juniper are prime examples) that look so much better after popping the grain with BLO before a finish, but I still want a durable finish on top.



and



> Since Woodturner's Finish is water-based you will most likely to continue to have problems. There is even a good chance that if you get Woodturner's Finish to stick to BLO you'll see problems a few years down the road.
> 
> What might be worth trying is to add a coat of dewaxed shellac over the BLO before you apply Woodturner's Finish.
> 
> Good Luck


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## NewLondon88 (Sep 27, 2012)

bradh said:


> Steve Busey said:
> 
> 
> > I've had people tell me that BLO helps to "pop the grain", whatever that means.
> ...



"pop the grain" means different things to different people, depending on
what they are doing. We often refer to it as an increase in contrast
between the various colors in the wood. ie. enhancing the grain. 
Oil does this wonderfully.. especially a penetrating oil that can get into
the surface and carry light with it. It can act as an optical channel to
enhance not only the grain, but the chatoyance.

Other woodworkers use 'pop the grain' to mean wetting the wood
so that the fibers expand and stand up higher so it can be sanded off.
Deliberately raising the grain and sanding it off allows them to use other
finishes that might raise the grain on their own.. causing a previously
smooth finish to become rough.


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