7. Quarterly Data (Unaudited) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
NET SALES	$ 8,998,000	$ 10,036,000	$ 9,850,000	$ 9,572,000	$ 7,993,000	$ 8,988,000	$ 9,963,000	$ 10,115,000	$ 38,456,000	$ 37,059,000
Cost of sales	7,982,000	8,452,000	8,680,000	8,247,000	9,075,000	7,877,000	9,010,000	9,221,000	33,361,000	35,183,000
GROSS MARGIN	1,016,000	1,584,000	1,170,000	1,325,000	(1,082,000)	1,111,000	953,000	894,000	5,095,000	1,876,000
Technical services and research & development	53,000	56,000	52,000	38,000	35,000	44,000	44,000	55,000	199,000	178,000
Selling, general and administrative expenses	1,182,000	1,068,000	1,062,000	842,000	1,447,000	943,000	1,039,000	1,052,000	4,154,000	4,481,000
Loss on disposal of assets	(1,000)	4,000	0	(1,000)					2,000	0
Loss on impairment of assets					2,912,000	38,000	0	0	0	2,950,000
OPERATING INCOME (LOSS)	(218,000)	456,000	56,000	446,000	(5,476,000)	86,000	(130,000)	(213,000)	740,000	(5,733,000)
OTHER INCOME (EXPENSE):
Interest expense, net	(37,000)	(43,000)	(47,000)	(50,000)	(31,000)	(37,000)	(60,000)	(80,000)	(177,000)	(208,000)
Income (loss) on foreign currency exchange rate	9,000	20,000	10,000	(89,000)	(3,000)	(157,000)	1,000	22,000	(50,000)	(137,000)
Other income, net	10,000	0	16,000	12,000	6,000	9,000	9,000	0	38,000	24,000
Total Other Expense	(18,000)	(23,000)	(21,000)	(127,000)	(28,000)	(185,000)	(50,000)	(58,000)	(189,000)	(321,000)
INCOME (LOSS) BEFORE INCOME TAX	(236,000)	433,000	35,000	319,000	(5,504,000)	(99,000)	(180,000)	(271,000)	551,000	(6,054,000)
Income tax (benefit) expense	(58,000)	142,000	(52,000)	75,000	442,000	22,000	(73,000)	(81,000)	107,000	310,000
Net income (loss)	$ (178,000)	$ 291,000	$ 87,000	$ 244,000	$ (5,946,000)	$ (121,000)	$ (107,000)	$ (190,000)	$ 444,000	$ (6,364,000)
Income (loss) per common share:
Basic	$ (.05)	$ .08	$ .03	$ .08					$ .13	$ (2.11)
Diluted	$ (0.05)	$ 0.08	$ 0.03	$ 0.08					.13	(2.11)
Basic and diluted					$ (1.97)	$ (0.04)	$ (0.04)	$ (0.06)	$ 0.13	$ (2.11)
Weighted average common shares outstanding:
Basic	3,542,000	3,542,222	3,402,000	3,014,000					3,376,000	3,014,000
Diluted	3,542,000	3,550,000	3,459,000	3,187,000					3,454,000	3,014,000
Basic and diluted					3,014,000	3,014,000	3,014,000	3,014,000		3,014,000