wood bleeding

[dennis bland]

I'm making a segmented vessel using blood-wood and maple , when applying the first coat of sanding sealer the blood-wood runs into the maple leaving faint red streaks . I sand up to 4200 grit and can see the red dust in the maple ,after blowing it with air the dust seems to be gone ,then the sealer brings it out and it runs together. Is there a remedy ?

Thanks
Dennis

 

[Richard Baker]

Dennis,
If you are sanding to/through 4200 you are making incredibly fine dust which can enter the tiniest places. Suggest you make 600 or even 400 your finest and last sanding grit. Then vacuum the piece w/ shop vac with clean filter (maximum suction) before hitting it with the compressed air. If you are using a wipe-on sealer, consider switching to a spray type.

Dunno about a remedy for the existing piece. Maybe resand with 320 and see if that goes deep enough to remove the unwanted color.

 

[Wyatt Holm]

I can't say much else other than use a spray on finish,or a different finish.

 

[Malcolm Tibbetts]

Dennis, you've received good advice. In my opinion, there's no reason to sand the wood past 600-grit. After the wood is well sealed, additional sanding can/could be done.

 

[MichaelMouse]

Never worked with bloodwood, but the extractives, including those that are used as dye, are generally more soluble in polar solvents than non-polar. Makes an alcohol-solvent shellac-based sealer a really poor choice, and a ketone-based lacquer questionable. I guess I'd try a little of each, and spray rather than swab, on some scrap to see what does the least harm.

 

[john lucas]

The best technique I have found for preventing the bleading is to put a coat of sealer down between each grit of sandpaper. I blow off the piece and then put a coat of sealer on and sand. Then blow it off put more sealer on and sand again.
I rarely go beyond 600 grit because with the finishes that I use I simply can't see the difference. I will sometimes sand the finish to very high grits.

 

[Michael Stafford]

I agree with John. I do not have the experience that Malcolm has with segmented work. I usually use a wipe on varnish mixture when I do segmented and I have not experienced the solvent problems that Michael describes but do not doubt they exist. Good vacuuming with a brush attachment seems to remove more dust than blowing with compressed air.

Most people do not have the visual acuity to see scratches much finer than 600 grit as Malcolm said. The only exceptions might be extremely fine grained dense woods such as ebony, cocobolo etc. Bloodwood is also very fine grained and dense if that is what you are using. It is sometimes difficult to distinguish between bloodwood, chakte kok, and red heart. I have had many more problems with dust bleed from red heart and chakte kok than with bloodwood. It is by far the most dense and hard of the three.