WEEK COMMENCING 27 MAY 2018
Your weekly Q&A Session with Chestnut Products
I hope you are well and enjoyed the long weekend, especially as it’s the last one for a few months. Hopefully the better weather is here to stay for a while, but I hope it doesn’t stop you getting into your workshops and creating.
I do try very hard not to repeat questions, but as the list of newsletters sent gets longer it becomes increasingly harder; I started keeping a database of the questions I’d included but it became unworkable. Then this week, I got one of those amusing stories by email which started by saying ‘We might have had this before but it’s worth another outing’. In the case of the joke it really wasn’t, but it occurred to me that we have lots of new readers sign up for the newsletter each week and that some questions can bear a repeat to keep them in our minds.
So with this in mind, I’ll move onto the questions – and about time too you say!
This week I’m returning to the question of thinning down products and in particular our Cellulose Sanding Sealer. It’s such a contentious issue. So much so that we’re going into our studio to make some more YouTube films soon and this will be the subject of one of them.
Regular readers will know that we do not recommend over-thinning the Cellulose Sanding Sealer; it’s a common myth that it needs to be thinned 50/50 to work better, but as a general rule this is incorrect. But there are a limited number of occasions where it is of benefit, and that’s what this week’s newsletter is about.
The first one is when working on a very fibrous, spalted or ‘punky’ piece of wood. You know the type, however careful you are and however sharp your chisels are you always get a patch or two of tear out which spoils the look of your piece. A thinned down coat of Cellulose Sanding Sealer (or indeed Melamine Lacquer) will help – apply it liberally to the affected area and allow it to soak in and dry. Once it has dried it will bind the timber together more and make it easier to cut, acting like a wood hardener to give a firmer surface to work on. (In the case of the Melamine Lacquer if you leave a few days to harden it’ll be even better, as it will give the lacquer time to cure a little).
Another use for a thinned sealer is when staining wood; some timbers are notoriously patchy in their absorbency (yes Pine, I’m talking to you!) and more stain will soak into some areas more than others. A coat of thinned sealer (cellulose or shellac) will assist here as well, as it will seal the absorbent areas as it is soaked in but will have very little or no effect on the non-absorbent areas – there’s not enough sealer present to do the job. Allow the sealer to dry and cut back as usual and the stain will go on much more evenly.
Both of the above help, I think, to show the need to use the sealer as undiluted as possible to get the best sealing result from it.
The other time you might want to add thinners to sealer is when you’re getting to the bottom of the tin. However much you limit the opportunity for solvent to escape from the can, natural evaporation occurs every time you open the tin (or carelessly leave the lid off!) meaning that by the time you get towards the end of the can the sealer has probably started to thicken up, so you might need to add some thinners to it to bring it back to its normal consistency. We don’t really see this as thinning the sealer, just returning it to its original state.
And there you go, we’re done for another week. I had a great time at the Lincolnshire Wolds Woodturning Society this week, thanks folks for your support and hospitality!
Have a good week and we’ll be back next Friday!