Just had the same on two jobs, had to run over with 16 first to stop the papers clogging One had black paint on beech and the other was some type of waxy seal on worn boards Real pain,
I can trump those...check this floor out, worst job i've ever done [and hardest] i badly miscalculated how hard it would be to sand off years of polish and dirt...the nightmares have only just stopped 123m2 of pain... http://www.woodfloor-renovations.co.uk/wooden-flooring-renovation-pictures-stalybridge-church-hall.htm
Glad it's not just me then. I almost told a old client this morning not to waste his money on the floorboards, but curiosity got the better of me and I started sanding an unsighted floor (I had done the rest of the house a few years back) I had pre warned him that if I started marching through belts and discs I would charge him accordingly. It had a 3-4mm of thick glue from where some spanner had glued underlay down!! To my amazement I used 1 x 24 Grit to cut it and edged 40 and low and behold it was spotless.... I've been doing this long enough to have seen it all but it goes to show that some floors can still surprise you...
Just to add to this, have any of you tried the Lagler Abrasives? I've been using them for a year now and nothing comes close and I have tried most companies on the market...
I've not tried the lagler abrasives, i use starke zirconia 10" belts and they just last for ages, well the 36-40-60 ones do...reasonable price wise as well when you work out how many m2 you get out of a belt...
How long is a piece of string.....job last week was 35 sq mt caked with wax used 2 40's and 1 60 grit followed with a dozen 40's and maybe 6 x 60's on the flip... And so on to completion. On parquet I could use them with no problem on another job. Trio discs are good for 30 odd sq mt before needing a change Price they are no different to Bona, with regards to the ceramics I am hearing varied reports about them over the pond...
I've tested some ceramic belts for a couple of companies, 36 grit and 60 grit ceramic belts on a 100m2 [well 96m2] job at the start of last year, the 36 grits did 50m2 each [easily] and there was still plenty left on them, 2 x 60 grits did 100m2 between them as well, the floor was maple strip and sanded off beautifully... A few months ago i tested some 50 grit ceramic belts for a very well known company, used them on old pine floorboards, after using zirconia 36 grit, 25m2 the room was and to be honest they didn't last very long, just about had enough on them to do the room, but on another job [oak boards] used the 50 grit ceramics again and they were good for over 80m2...the ceramic belts are mainly impressive but quite expensive at about £8.00 a pop.
On a cost v performance basis i don't think you can beat a good Zirconia belt tbh...£7 or £8 a pop for a 36 grit ceramic belt is a bit much if you ask me. But...on certain floors they will certainly be cost effective and perform very well for a lot of m2, but on other floors perhaps not so well...horses for courses...its just finding the right balance for your needs...
When I had an engineered flooring production in Mid Wales one of my customers who used to also sell reclaimed asked if I could process his reclaimed pitch pine boards into engineered flooring. Said it had been professionally de-nailed ect so for me it was no problem and I took the job, I knew it was going to be a little difficult bit I wanted to do a pitch pine reclaimed engineered board. First issue was that the de-nailing was far from professional and a lot of the time they had removed the nail but only half as half had rusted off in the board so the whole 300m2 worth it took 2 days with 3 of my guys and metal detectors. What maid it worst is the floor must of came from some old factory and it had years and years of different coatings, spilled liquids and also these small chain links which were not an issue for when I had to saw into lamels but were a right pain when using a metal detector to find nails ect! Once done we regularized the the widths and moisture content then started to saw into lamels finding even more and more metal and destroying band saw blades left right and center, then we sanded the lamels to the correct thickness. We had a 6 head(3 top, 3 bottom) sander that calibrated off top and bottom head a real heavy duty piece of kit but this surface was like stone at times I could not believe how hard it was.....After everything with lost time and machine component damage I think we broke even!! The floor looked stunning when it was finished but the years and years of abuse I was sanding the pitch pine slower and less of a amount being sanded out at each pass than 260mm+ wide Oak and this was only 135mm ad 155mm wide! Lesson learnt for me that week!
