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Ripple effect with drum sander

Posted: Tue Feb 05, 2008 9:52 am
by tuco100
Hi i recently hired a drum sander and edging sander to sand my parquet floor (1st time ive done it) the job was going great until i got to the 80 grit fine grade paper ! i found that once i started using the fine grades (80 and 120 grit) that i got what i can best describe as a very slight ripple effect on the floor , i could very slightly feel a very small judder in the sander as i walked along with it . I tried it in both directions (fractionally better) and was very fussy abut how tight and central i got the sheets on the drum. thing is i can't work out whether it was me at fault or is this unique to a drum sander . I would really appreciate some info or advice on this thanks

Posted: Tue Feb 05, 2008 8:25 pm
by Tall Tone
Hi Tuco100
Did the sander have a drum with abrasive paper you cut to length and then fit around the drum and secure with a locking bar, or did it have a continuious piece of abrasive which slides over the drum?
Regards
TT

Posted: Wed Feb 06, 2008 9:19 am
by tuco100
Hi TT it was the drum type which wrapped around and used a locking bar to secure it but the sheets where purpose built you didn't have to cut them . I thought this was the only type you could hire ?
regards tuco100

Posted: Wed Feb 06, 2008 10:06 am
by thedoctor
See our project on sanding a timber floor. We have a company in there who supply all makes of sanders for every eventuality.

Posted: Wed Feb 06, 2008 2:15 pm
by Tall Tone
Due to the way they are set up most Hire-shops use a "Hiretec" Machine. These are robust, basic and very light. Modern machines which are designed for the professional market like Bona and Hummell are heavy, very powerful but also very easy to use when you know what you are doing.
Your problem most likely stems from the speed you passed over the wood. In every rotation of the drum the abrasive misses a little bit due to the locking mechanism gap. This is most notable on the finer abrasives. In effect you have a floor sanded to 100 grit with lines only sanded to 80 grit. Modern machines as mentioned use continuous abrasives, these do not suffer from this problem.
Solution, hire a better sander, or blend the marks together with a buffing machine and a sanding screen.
Hope this helps a bit.
TT

Posted: Wed Feb 06, 2008 9:43 pm
by tuco100
hi tt thanks for the advice and info , would i have been better walking a bit faster with the finer grades ?
thanks again

Posted: Thu Feb 07, 2008 9:27 am
by Tall Tone
Hi
Actualy the reverse, slower is better. Obviously not so slow you wear through the wood.
I tend to pace with one foot in front of the other to keep the speed constant.
Not so sure about the machine you hired but my Bona Belt tends to cut smoother as you walk slowly backwards. That said it has a continuous belt. I still run a buffer machine over the surface to blend everything together because the marks you get from an edge machine are different to those you get from a drum.
Hope this helps.
TT